Read: Cancer Prevention: Rethink Your Diet as Well as Your Smoking.

Hamzany concludes that exposure to cellphones causes oxidative stress, which harms human cells and DNA and contributes to a "carcinogenic effect." He adds that his study corroborates the results of so many others, which find correlation, not causation, between cellphones and cancer risk. "It does give us an idea of the harmful effect of the telephone," he says, advocating caution rather than discontinuing cellphone use. "Maybe use it less often, maybe not expose children to it," he tells U.S. News. "Maybe there is a kind of additive effect, and in the long run it could cause tumors."

In May 2011, the International Agency for Research on Cancer convened a group of 30 scientists in Lyon, France to review wide-ranging studies on radiofrequency electromagnetic fields, the radiation associated with cellphones. Their conclusion: Cellphones are "possibly carcinogenic to humans," but there is "limited evidence in humans and in experimental animals."

The conclusion took into account an international study, which assessed thousands of people over the course of a decade and found a slightly increased cancer risk among the group with the greatest exposure to cellphones but did not prove a causal connection.

jīng diǎn wù huì xiào huà 4 gè ,bào xiào lè fān tiān ！

1、tóng xué A，nán ，àn liàn nǚ tóng xué de C hěn jiǔ le ，fà duǎn xìn xiàng qí biǎo bái ，duǎn xìn shuō “wǒ dì yī yǎn kàn dào nǐ wǒ jiù xǐ huān shàng nǐ le 。” C： nǐ dì yī yǎn kàn dào wǒ shì shén me shí hòu ？ A： jiù shì kāi xué dì yì tiān ，kàn jiàn nǐ hé jiā rén yì qǐ lái xiào le ，nà shí nǐ chuān de qún zi tè piào liàng C： nà tiān wǒ méi chuān qún zi ，chuān qún zi de nà gè shì wǒ mā ！